Speed hardening system improves tunnel construction

BASF claims that its latest innovation will help improve efficiency in tunnel construction operations. Developed by BASF's Construction Chemicals division the new Crystal Speed Hardening system (CSH) is an advanced admixture technology aimed directly at the tunneling market.
February 14, 2012 Read time: 2 mins
The new concrete concept from BASF will help cut curing times
2645 BASF claims that its latest innovation will help improve efficiency in tunnel construction operations. Developed by BASF's Construction Chemicals division the new Crystal Speed Hardening system (CSH) is an advanced admixture technology aimed directly at the tunneling market. This product offers increases in efficiency for concrete casting, both for precast segments and cast in-situ linings. The fast-curing concept allows the removal of formwork at an earlier stage of the casting process and increases productivity. The product can shorten the length of time that formwork or shuttering has to be kept in position or by reducing the number of sets of formwork required. In addition to supporting efficiency, the system helps reduce CO2 emissions, optimises material use and meets high quality specifications according to the firm. It does so by providing high early strength development whilst balancing the requirement for an optimum mix through the use of more binding material and reduced clinker content.

The CSH concept uses a new hardening accelerator, X-SEED, to boost early strength development by modifying the action mechanism of cement hydration. X-SEED is made of suspended CSH-seeding crystals: the material added is of the same nature as the final hydration products from the cement reaction with water. As the suspended crystals are considerably smaller than microsilicas, the surface is much more beneficial for accelerating the crystal growth during the early stages of concrete hardening. The product has already been tried and tested in a number of tunneling trials. The abbreviation CSH also refers to calcium silicate hydrates; the cement hydration products responsible for the compressive strength of concrete. Hydration speed depends on the chemical composition of clinker and other cementitious materials. To simplify the science, by using BASF's X-SEED admixtures, a liquid suspension of synthetic crystal seeds on the nano scale, the growth of calcium silicate hydrate crystals is significantly accelerated.

Road Structures

For more information on companies in this article

Related Content

  • Underground routes for highways
    July 20, 2012
    Increasingly, and where possible, roads are being built in tunnels often for environmental reasons, writes Patrick Smith As part of the new M7 motorway development in the southwest of Ireland, the four-lane route crosses the River Shannon near Limerick, before it flows into the Atlantic. Centrepiece of the 10km long Limerick Southern Ring Road is the required tunnelling (675m long), which including the north and south entrance and exit ramps, means it will be 915m long. Completion of the work is planned for
    Read More
  • Polymer enhanced bitumen technology improves performance
    July 11, 2012
    As overall traffic volumes increase, the contribution from commercial vehicles with increased axle loads is growing, putting ever more strain on roads and highway maintenance budgets. Highway authorities are looking for products that will be able to cope better and are more cost effective over the life of a road. Technical innovation is the only way to answer this challenge effectively, says BP Bitumen, one of a number of specialist companies involved in bitumen technology.
    Read More
  • Improving a key route through Florida
    November 9, 2015
    Upgrading a key route through Florida – novel construction techniques are helping widen a road in difficult geological conditions – Lucio Garofalo reports. A major road widening project underway in Florida is due for completion soon. The work will improve an important section of road, reducing congestion at peak period and cutting travel times for drivers. The US 331/SR83 highway runs for some 79km and provides an important link in Florida’s Panhandle area, as it connects with Route 98.
    Read More
  • Feeling the burn, with Benninghoven
    October 16, 2024
    For industrial purposes such as asphalt production or mobile off-highway machines, hydrogen offers the option of a green fuel that helps cuts CO2 emissions - Mike Woof writes
    Read More

Highlighted Content